This application addresses broad Challenge Area (05) Comparative Effectiveness Research and specific Challenge Topic 05-MD-101*, Social Determinants of Health. We propose to conduct a comparative effectiveness analysis and cost effectiveness analysis to investigate the benefit of health insurance reform on addressing cancer health disparities. The social determinants of cancer health disparities have been described, which include access to quality health care, and insurance to pay for quality care. There is a need to investigate the comparative effectiveness of public health policies that improve access and quality of health care through improvements in health insurance as a mechanism to overcome social determinants of cancer health disparities. Specifically, we propose to investigate the comparative and cost effectiveness of health insurance reform that was instituted in 2006 in the Commonwealth of Massachusetts, on the cancer outcomes of traditionally underserved women who have abnormal cervical and breast cancer screening studies. We propose to conduct this analysis using a unique database our research group has collected as part of the Boston University Patient Navigation Research Program. We have collected detailed clinical, demographic, insurance, and outcome data on over 3300 women, the entire cohort of women with abnormal breast and cervical cancer screening studies between 2004-5 and 2007-9 at 6 community health centers in Boston. Our proposed research is unique both in its approach and in the dataset to address the approach. We have collected data on a complete clinical cohort of women that health insurance reform specifically seeks to support. This dataset has the ability to observe the findings of the "natural experiment" of Massachusetts Health Insurance Reform, in that we began our data collection 2 years prior to insurance reform, and continued 2 years after its implementation. As many look to the Massachusetts experience to develop a national health insurance plan, our research has major impact potential on national policy. There is a critical need for empiric data on the clinical impact of health insurance reform. Our results will provide empirically derived comparative effectiveness data that is of critical interest to policy makers locally and nationally seeking to assess the benefits of insurance reform. We propose to investigate the comparative and cost effectiveness of health insurance reform that was instituted in 2006 in the Commonwealth of Massachusetts, on the cancer outcomes of traditionally underserved women who have abnormal cervical and breast cancer screening studies.